The Twentieth Dynasty of Egypt (notated Dynasty XX, alternatively 20th Dynasty or Dynasty 20) is classified as the third and last Dynasty of the Ancient Egyptian New Kingdom period, lasting from 1189 BC to 1077 BC. The 20th Dynasty and the 19th Dynasty furthermore together constitute an era known as the Ramesside period.

Upon the death of last pharaoh of the 19th Dynasty, Queen Twosret, Egypt descended into a period of civil war, as attested by the Elephantine stela built by Setnakhte. The circumstances of Twosret's demise are uncertain, as she may have died peacefully during her reign or have been overthrown by Setnakhte, who was likely already middle aged at the time.

A consistent theme of this Dynasty was the loss of pharaonic power to the High Priests of Amun. Horemheb, a pharaoh of the 18th Dynasty, had restored the traditional Ancient Egyptian religion and the priesthood of Amun after their abandonment by Akhenaten. With the High Priests now acting as intermediaries between the Gods and the people rather than the Pharaoh, the position no longer commanded the same kind of power as in the past.

Setnakhte stabilized the situation in Egypt, and may have driven off an attempted invasion by the Sea Peoples. He ruled for about 4 years before being succeeded by his son Ramesses III.

In Year 5 of his reign, Ramesses defeated a Libyan invasion of Egypt by the Libu, Meshwesh and Seped people through Marmarica, who had previously unsuccessfully invaded during the reign of Merneptah.

Ramesses III is most famous for decisively defeating a confederacy of the Sea Peoples, including the Denyen, Tjekker, Peleset, Shardana and Weshesh in the Battle of the Delta and the Battle of Djahy during Year 8 of his reign. Within the Papyrus Harris I, which attests these events in detail, Ramesses is said to have settled the defeated Sea Peoples in "strongholds", most likely located in Canaan, as his subjects

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